If you want to block certain visitors from your project you can set an IP block in Audience. You do this by opening up Audience settings and adding a Geo data statement to the audience board. Make sure that IP is selected and then change to IS NOT in the second dropdown. Then add the IP number(s) you want to block by entering one IP address at a time and hitting enter. Click Save & close when you are done and then click Save in the upper right to save your Audience.
Make sure to check your Audience settings by opening up a preview of the project.
In the example below the following IP addresses should result in Audience FALSE:
220.127.116.11, 18.104.22.168, 22.214.171.124